I will never buy a HDMI cable!! NO ONE needs it anyways! [Text View]

penngray

04-24-07, 01:56 PM

From the CEO of Noethings.......

As the CEO and lead designer for Neothings, I can tell you exactly why we are not currently offering a HDMI distribution system. I also can guess that the reasons why my competitors do not are similar.

First let's identify a few of the core requirements of a whole house HD distribution system:
1) 4 to 8+ inputs
2) 4 to 16+ output zones
3) Must support mixed makes/models and resolutions of displays
4) Different zones have different audio requirements (analog or digital)
5) Zones typically 25 to 250 feet away from centralized rack
6) Solution must fit into the typical project workflow (prewire, terminate, finish)

These requirements are typical for a custom residential installation, and are also common for many light commercial jobs as well.

When we have looked at designing a product to meet these needs in the past with analog video, the solutions are reasonable. There are many analog ICs available to design around and they are well characterized. Solutions for req. 1 and 2 are basically a matter of good electrical design and selecting an IC vendor that meets your design goals.
The solution for req. 3 comes from the fact that there are established standards for analog SD and HD video. Formerly in the hands of the EIA, now the CEA maintains 770.1 - 770.3 which spells out 480i through 1080i, and as a result nearly every HDTV on the market support these interfaces, regardless of make/model, or native resolution.
Req. 4 is met by support of either two channel analog audio (built into the display) or nearly every surround processor that can handle Dolby Digital or DTS. Source devices will have one or the other, or both, creating sort of a dual common denominator for audio reproduction and a choice of audio design per zone.
Req. 5 is helped by the fact that HD analog video has less that 75MHz of bandwidth. Given it's one way nature, the signal can be transmitted, boosted, equalized, and driven over twisted pair cable such as CAT5 for even longer runs of up to 1000'.
Req. 6 is met by purchasing cable in bulk, installing before wall are in, or cutting into existing walls, and coming back to the jobsite after several other trades have stepped on, hammered, and otherwise abused the raw cables. After that cables can be cut to fit, field terminated, and finished in a professional manner with a wall plate. Final install of the equipment will be plug and play.

Now when we try to meet these requirements with HDMI, we run into the following:
Requirements 1 and 2 are made difficult by the data bandwidth to support HD. Each HD signal will probably be about 2.3Gbit/sec, but can be as much 4.5Gbit/sec. IC solutions to move and aggregate of 36-72Gbit/sec do exist, but are expensive.
The 3rd req. is one of the more difficult ones to solve. By nature of how HDMI works, the source device has two way communications with the display to decide on a resolution to use. However if that source device is going to feed 16 random displays, what resolution should it output? Another expensive solution exists by processing every image for every display, but along with that you will lose the 1:1 pixel mapping that people believe they will get by going digital in the first place.
Another reality to this requirement is ongoing HDCP issues. With each new HDMI device introduced to the system, the odds of having all devices communicate properly with full repeater support are not impressive.
The issues with req. 4 are similar to req. 3, but again there are solutions to that by having an audio processor for each output zone, again adding to the cost.
Requirement 5 is one that most here are familiar with, and that is length limitations of HDMI. Sounds like most are having decent success with short distances, but beyind 100 feet will usually require more exotic/expensive solutions such as fiber optic cable.
Req 6 has not really been solved to my knowledge. Really the only solution here is to preinstall conduit large enough for the HDMI connector, and install a premade cable. Field termination is not really an option.

Not to rag exclusivley on HDMI, IEEE1394 has it's own issues:
Not universally available on source devices or displays.
Similar issues with HDMI on field termination of cables.
To give 1394 some credit, they do have the length issues worked out with 1394B, and due to the compressed nature, the mixed resolution scenario works itself out since each display would have it's own decoder built in.

HDMI is not a good solution for video distribution. It's market is in the 'last mile', or last 15 feet I should say, of a video interface.
In reality we should not be trying to force HDMI to be something it is not. Instead the solution is in another digital solution to take care of the consolidation and distribution within our environment, and then possibly letting HDMI connect the last 15 feet.

However this is where it gets complicated with all this DRM and copy protection stuff. The current legal and licensing environment is not allowing designers to innovate, and finish the job. To complete the all digital home, we need to be able to use 1394 networks, LANs, the Internet, or whatever tomorrow may bring, and do it without having to tip toe around dozens of oppressive licenses and lawsuits such as the two year long dispute between the DVDCCA and Kaliedascape.

So the bottom line is that we are not waiting for the technology, but instead we are waiting for the legal framework to make products like this. Without that, analog video is necessary, and most everyone in the industry knows it. I wouldn't count on it going anywhere until there is a viable solution that can replace it. Currently there is not.

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Neothings | Bill's Blog | New Video Primer Project

From Trent at Audio Authority

Bill hit it right on the head. HDMI is simply not well suited for long distance video distribution in the eyes of many of the video distribution players for the following reasons:

1) Inherent distribution distance limitations
2) Continuing handshaking and compatibility issues
3) Cables not field-terminable
4) High costs of the component parts to build an HDMI-based system

Theoretically, numbers 2) and 4) will improve, especially now that SimplayHD certification exists and Intel has released the HDCP spec to manufacturers (it's really a miracle that anything worked before that). However, unless there is a complete breakthrough in AV over Cat 5 systems (which seem to be unreliable at this point in many cases, and are still limited to about 150 foot runs) or fiber becomes less expensive, you have a serious challenge for most installations.

We continue to build analog distribution systems because it's the best way - they work, and are much less expensive and simpler to engineer.

Editorializing here, but I don't think Component Video is going anywhere. I don't believe the ICT (Image Constraint Token) will be activated. Copy protection on Blu-ray and HD DVD has been broken, and digitally perfect, bit for bit copies can be made using a $150.00 software program. The reason for not providing unprotected component output of HD resolutions has been stated as a measure to "prevent copying". Does ANYONE have a device that can record a real-time, baseband, component video signal output into a lossless storage device without serious compression? No.

That means that activating the ICT would be a foolish, and totally ineffective method of stopping piracy. Would you rather have a lossy analog copy or a hard disk replication?

Hopefully content providers would realize this.

All that said...

If a cost-effective design that allows for 100% reliable use of HDMI in a matrix system format becomes a reality, we will be right on the forefront of development.

However, the biggest problem remains the issue of distribution distance (difficult to address) and compatiblity issues. It would be possible to build a 100% Simplay Certified, HDMI ATC tested HDMI matrix, and still have huge numbers of complaints and product returns because of all the poorly-implemented HDCP and HDMI systems out there.

Trent

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Trent Davis
Audio Authority Corp.
Expert Manufacturers of HDMI, DVI, Component, and Audio Switching Products, Distribution Amps, A/V over Cat 5 Products, Video Converters, and More